Community advocates in the border neighborhood of San Ysidro fear U.S. government plans to inspect cars before they leave the U.S. will cause more congestion and pollution.

SAN DIEGO  On an average day, some 200,000 people cross the border north and south between Tijuana and San Diego, making the San Ysidro port of entry the busiest in the world -- and for commuters, a frustrating one. The wait to enter the U.S. regularly approaches three hours or more.

Now, as part of an ongoing multi-year expansion project at the port, the U.S. government is more than doubling the number of inspection booths, with the hope of cutting that wait down to 30 minutes tops.

And for the first time, the U.S. will also construct booths to inspect cars before they head into Mexico -– 12 of them, according to the government’s preliminary designs.

“Most of our energy is clearly focused on travelers and goods coming into the United States,” said Chris Maston, the Customs and Border Protection official who oversees land ports of entry along the border with Mexico. “But we do recognize that we have a responsibility to perform those outbound checks, and we’re going to do that.”

In fact, U.S. customs officers have been inspecting cars before they head into Mexico since 2009, in an attempt to stem the southbound flow of money and weapons that have helped fuel the Mexican drug war.

Government statistics show that southbound inspections yielded seizure of $86 million, roughly 200 weapons and some 25,000 rounds of ammunition along the border in the first two years. But the inspections have been sporadic, with officers standing in traffic and waving cars through. Border officials wanted more permanent infrastructure for those inspections.

What’s still not clear is what effect that new infrastructure will have on the southbound flow of traffic and whether it will create backups similar to the northbound wait.

Community Concern

In San Ysidro, the largely immigrant San Diego neighborhood that abuts the border, there is concern that those southbound inspection booths will do just that, especially if they usher in round-the-clock southbound inspections.

David Flores is an architect and planner who works for a San Ysidro social service nonprofit called Casa Familiar. He said he’s tried, mostly in vain, to work with officials at Customs and Border Protection and the General Services Administration – which is in charge of construction – to anticipate the impacts that kind of congestion will have on the surrounding community, and to try to address it.

To illustrate his concerns, Flores took me to the playground at San Ysidro’s Willow Elementary School. It’s an attractive new campus just a quarter-mile north of the border crossing.

The playground’s back fence separates the school from the southbound lanes of Interstate 5.

“This is what really alarmed us, actually,” Flores said. “Once we said, wait a minute, if all these vehicles are going to be inspected by both the U.S. and Mexico, and this is the route, what is going to happen to Willow School? We’re talking about thousands of vehicles daily that are going to be backed up.”

Those thousands of cars waiting to get into Mexico would be idling within feet of the elementary school campus, spewing exhaust.

“If you think back to elementary school, what’s the first thing your teacher did when you got into the classroom?” Flores said. “She opened the windows to let in the fresh air. But if they did that here, it would be a disservice.”

After learning of the government’s plans, Flores and a San Diego State University researcher started taking air samples at several sites in San Ysidro, and found, to no one’s surprise, that the closer they got to that long line of cars waiting to get into the U.S., the more harmful the air, full of stuff like black carbon.

He fears those pollution levels will balloon once the southbound inspection booths come in. Armed with the data he’s collected, he’s trying to get General Services Administration and other government officials to take that into account as they move forward with the project.

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Chris Maston, a spokesman for U.S. Customs and Border Protection, talks to KPBS about the new border crossing rules.

Uncertainty Remains

GSA officials say they just don’t know yet what the impacts will be. That phase of construction is a few years away, and still lacks congressional funding. Langston Trigg, the GSA’s project manager for the port expansion, said the design could change by the time construction starts.

“Because technology’s continuing to change and evolve, there’ll be more electric cars hopefully, there’ll be a different emphasis on how we process cars, so that’s kind of unknown,” he said. He also said the current plan to double the number of southbound lanes would be likely to offset congestion that might be created by southbound inspections.

And Chris Maston of Customs and Border Protection says the arrival of the new booths won’t necessarily mean more southbound congestion and backups.

He said the inspection booths are intended in large part to protect officers who currently stand in traffic during southbound inspections. He said there’s no current plan to alter the existing “pulse and surge” policy of more sporadic southbound inspections.

“We don’t have any intention at this point of putting up a full-blown, 24-7, it looks like the same thing we do on the inbound side. It’s not that at all,” Maston said.

But Flores isn’t taking chances.

He said this is an issue of environmental justice, and that San Ysidro’s population already suffers from other health problems like diabetes without having to worry about breathing dirty air.

He’s started talking to local officials from the Environmental Protection Agency, and is looking into filters for school air conditioners, a program that raises flags on school flag posts to alert parents on days with poor air quality, and a kind of building-paint that captures air pollutants.